Conditions

Three Way Catalytic Converter







Fault symptoms
CHECK ENGINE lamp on.

Conditions
Diagnosis not yet performed during this trip

Catalytic converter heating:
- Vehicle speed >0 km/h
- Open throttle
- Engine speed (rpm) x load (kpa) = >60000
- Total acceleration >15 sec.
- Above conditions fulfilled for 120 sec.

Evaluation of catalytic converter
- Speed 30-100 km/h
- Open throttle
- Engine speed (rpm) x load (kpa) = 60000 - 120000
- Engine coolant temperature >60C (>140F)
- Oxygen sensor 2 >0.4 V on some occasion during this driving cycle

Voltage changes from oxygen sensor 2 are corrected with respect to load and engine speed and are totalled in a measuring window determined by oxygen sensor 1. If the total exceeds a calibrated value, the fault criteria will have been fulfilled.

Diagnostic help
The capacity of the catalyst can be reduced temporarily or permanently for the following reasons:
- lead or sulphur in the fuel.
- fuel additives
- additives in the engine oil when oil consumption is abnormal

Checking the wiring harness. Intermittent faults may occur in connection with short circuits and open circuits. Jiggle the wiring harness at several points and in several directions to locate any problems in the wiring, including intermediate connectors. Observe the multimeter, scan tool or test lamp during the check.